SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Aging induces a dysregulation of immune and inflammation functions that may affect protein synthesis rates in lymphoid tissue and plasma proteins. We quantified in vivo synthesis rates of thymus, spleen and plasma proteins, including albumin and acute phase proteins, in adult (8 mo old) and old (22 mo old) rats using the flooding dose method [L-(1-(13)C) phenylalanine]. Immunosenescence was reflected by thymus atrophy and spleen hypertrophy in old rats but not in adult rats. A low albumin plasma level associated with high concentrations of fibrinogen, alpha(2)-macroglobulin, alpha(1)-acid glycoprotein and proteins other than albumin revealed a low grade inflammation in old rats. Protein fractional synthesis rates (FSR) and protein synthesis efficiencies of thymus were 29 and 26% lower in old than in adult rats, respectively; these variables did not differ in spleen. Protein absolute synthesis rates (ASR) of the thymus and spleen were 76% lower and 67% greater in old than adult rats, respectively. The FSR and ASR of albumin and other plasma proteins were greater in old than in adult rats. Protein synthesis measurement is a valuable nonimmunological tool to assess, in vivo, immune and inflammatory variables. Alterations in secondary lymphoid organs and plasma protein synthesis may contribute to the significant repartitioning of amino acids in old compared with adult rats and may be involved in sarcopenia.
Efficient polyacrylamide gel electrophoresis of labile proteins and protein complexes is reviewed. If only 0.001-0.01% SDS is dissolved in the electrode buffers, the detergent does not exhibit denaturing activity and guarantees high quality of electrophoresis. Even the structure and oxygen-producing activity of the labile photosystem PS2 are preserved after electrophoretic separation of photosynthetic pigment--protein complexes from Anacystis nidulans R2 or other cyanobacteria. The overall spectra of absorption or fluorescence of isolated pigment--protein complexes are equal to the corresponding spectra of the photosynthetic membrane. The distribution of chlorophyll molecules between the components of the photosynthetic apparatus coincides in spectral analysis data and gel fraction densitometry. More than 15 electrophoretic fractions of pigment--protein complexes of chloroplasts from green algae and higher plants were observed including some fractions of PS1, some spectrally different forms of light harvesting pigment--protein complexes, and their oligomers. High resolving capacity of electrophoresis was demonstrated by separation of plasma proteins. Low denaturing activity and low thermal dissipation of the electrode buffer solution allow the use of large diameter tubes (3.5 and 8 cm) in polyacrylamide gel electrophoresis. The cell destruction time and the membrane dissolving time are minimized. The method of electrophoretic staining of the gels was tested.
The plasma proteins are a significant contributor to the total weak acid concentration as a net anionic charge. Due to potential species difference, species-specific values must be confirmed for the weak acid anionic concentrations of proteins (Atot) and the effective dissociation constant for plasma weak acids (Ka). We studied the net anion load Atot of equine plasma protein in 10 clinically healthy mature Standardbred horses. A multi-step titration procedure, using a tonometer covering a titration range of PCO2 from 25 to 145 mmHg at 37 degrees C, was applied on the plasma of these 10 horses. Blood gases (pH, PCO2) and electrolytes required to calculate the strong ion difference ([SID] = [(Na(+) + K(+) + Ca(2+) + Mg(2+))-(Cl(-) + Lac(-) + PO4(2-))]) were simultaneously measured over a physiological pH range from 6.90-7.55. A nonlinear regression iteration to determine Atot and Ka was performed using polygonal regression curve fitting applied to the electrical neutrality equation of the physico-chemical system. The average anion-load Atot for plasma protein of 10 Standardbred horses was 14.89 +/- 0.8 mEq/l plasma and Ka was 2.11 +/- 0.50 x 10(-7) Eq/l (pKa = 6.67). The derived conversion factor (iterated Atot concentration/average plasma protein concentration) for calculation of Atot in plasma is 0.21 mEq/g protein (protein-unit: g/l). This value compares closely with the 0.24 mEq/g protein determined by titration of Van Slyke et al. (1928) and 0.22 mEq/g protein recently published by Constable (1997) for horse plasma. The Ka value compares closely with the value experimentally determined by Constable in 1997 (2.22 x 10(7) Eq/l). Linear regression of a set of experimental data from 5 Thoroughbred horses on a treadmill exercise test, showed excellent correlation with the regression lines not different from identity for the calculated and measured variables pH, HCO3 and SID. Knowledge of Atot and Ka for the horse is useful especially in exercise studies and in clinical conditions to quantify the mechanisms of the acid-base disturbances occurring.
The concentrations of 25 plasma proteins were measured in 22 patients with membranous nephropathy. For some large proteins, the plasma concentrations were increased; there were also large proteins with low plasma concentrations, but small or medium-sized proteins showed uniformly lower plasma concentration than the controls. Plasma colloid osmotic pressure (pi) and viscosity (eta) were not interrelated but showed positive and significant correlations with plasma concentrations of small and medium-sized proteins (pi) and plasma concentrations of large proteins (eta), respectively. Nephrotic plasma is not efficient in maintaining plasma pi but highly efficient in maintaining plasma eta. High plasma fibrinogen concentrations and low antithrombin III concentrations may predispose to thrombosis, and low IgG concentrations may account for the higher predisposition to bacterial infection. The relative composition of nephrotic plasma is heavily dependent on the size of the different proteins. Plasma pi and eta are also maintained by the relative preponderance of different plasma proteins.
Explore the source record for details and available documents.
Five per cent heat treated stable plasma protein solution (SPPS) has been rapidly infused into 25 patients, as fluid replacement during large volume plasmapheresis. Reactions were produced in 20 patients. Subjective symptoms of flushing, nasal stuffiness, fullness and throbbing in the head, colicky abdominal pain, metallic taste or apprehension were observed in 16 patients, and 11 patients became hypotensive with an average systolic pressure of 70 mm Hg. These observations support earlier reports of hypotension due to rapid SPPS infusion, and document the occurrence of subjective symptoms which may be the harbingers of a hypotensive reaction. In view of the known presence of a bradykinin-like substance in some heat treated plasma protein solutions, hypotension during SPPS infusion should be interpreted with caution in the light of these findings.
The plasma protein binding of flurbiprofen was studied using equilibrium dialysis. Dialysis was carried out using plasma samples obtained from five of 15 subjects participating in a crossover bioavailability study. During the course of this study subjects received doses of 100, 200, and 300 mg of flurbiprofen as tablets, and 100 mg as an aqueous solution. Seven samples from each of the four treatments (28 samples/subject) were utilized. An additional 14 samples (seven concentrations prepared in duplicate were prepared using blank plasma obtained from each subject. Concentrations of bound (Cbd) and free (Cfd) flurbiprofen were determined at dialysis equilibrium using a radiotracer technique. Binding curves were constructed for each subject using data obtained from these 42 (28 ex vivo and 14 in vitro) samples. The data was well fitted to a modified Scatchard equation with the addition of a linear term. Although the plasma protein binding of flurbiprofen was nonlinear, within the range of concentrations encountered in the clinical setting, it is minimally so. The Cb/Cf ratio averaged 1524, indicating that in plasma, flurbiprofen is greater than 99.9% bound. The results support the observation that for doses of flurbiprofen usually encountered clinically, the drug obeys linear kinetics.
Explore the source record for details and available documents.
The rate of plasma protein turnover is more rapid in dogs receiving adequate dietary protein than when a diet devoid of protein is fed. Both albumin and combined globulins are involved in this change. The difference in turnover is reflected in a total protein half-life of 4.8 days with protein feeding versus 7.8 days without protein in the diet and in the metabolism of 1.0 and 0.65 gm. per kilogram of body weight per day on the respective diets. Additions of dietary protein from 10 to 30 per cent caused no further increase in the rate of plasma protein turnover. With protein depletion due to plasmapheresis and a very low protein diet there is evidence of reduced protein metabolism as indicated by nitrogen retention as well as a reduction in total plasma protein breakdown and interchange of isotope between plasma and tissue proteins. Following introduction of labeled plasma protein into the circulation the net amount of isotope transferred to tissues has been computed from the difference between total plasma protein breakdown and combined C(14) excretion in urine and expired air. In animals receiving adequate dietary protein, tissue transfer amounts to 70 per cent of the total lost from the plasma proteins each day while the percentage rises to 85 in depleted dogs deprived of protein. In dogs with both plasma and tissue proteins labeled it can be estimated that, under conditions of protein feeding, an amount of C(14) approximately equal to that lost from the plasma must recycle to account for the observed decrease in Apparent plasma protein turnover rate, (t(1/2) of 15 versus 5 days). Without protein in the diet the isotope contribution of the tissues to the maintenance of plasma protein levels must be as great as or greater than that transferred in the opposite direction.
Explore the source record for details and available documents.
Human plasma was incubated with cisplatin over 24 h. Ultrafilterable platinum and platinum reactive with DDTC were determined at regular time intervals during incubation. At each time point more platinum reacted with sodium N,N1-diethyldithiocarbamate (DDTC) than was available as ultrafilterable platinum. At 24 h 70% of total platinum (10% ultrafiltrable platinum and 60% protein-bound platinum) reacted with DDTC. This means that cisplatin bound to plasma proteins can--at least in part--still react with strong nucleophiles.
Seminal plasma protein adsorption by boar spermatozoa was examined using ejaculated sperm from vesiculectomized boars and seminal plasma from vasectomized boars. Sperm adsorbed 14 pg protein/sperm in 10 min. When seminal plasma proteins were radiolabeled, most of the adsorbed radiolabel was present in low M(r) proteins, particularly a 12700 M(r) protein. A 349300 M(r) seminal plasma protein was also readily adsorbed. Three radiolabeled seminal plasma proteins (307600, 165400 and 7400 M(r)) were not detected on the sperm; either they are not adsorbed by the sperm or the sperm were previously exposed to these proteins in other accessory sex gland fluids and had already adsorbed them. A 29100 M(r) sperm protein was also radiolabeled (4.9% of the adsorbed radiolabel), although there was no corresponding seminal plasma protein. Large quantities of seminal plasma protein (particularly low M(r) proteins) are adsorbed by sperm not previously exposed to seminal vesicle secretion. The functions of these proteins are yet to be determined.
Explore the source record for details and available documents.
The plasma protein and red blood cell binding profile of bismuth was investigated as a function of bismuth concentration. The binding of bismuth to human serum albumin, bovine serum albumin, and human plasma was also evaluated by ultrafiltration and the data analyzed by nonlinear regression techniques. The binding of bismuth to plasma proteins was nonlinear and decreased as a function of incubation concentration and appeared to be limited by the number of ionized l-cysteine residues available for binding. In the concentration range studied, bismuth was associated primarily with the red blood cell fraction of whole blood obtained from male Sprague Dawley rats. The data indicated that binding to proteins was of moderate affinity, and in whole blood it was present primarily in the red blood cell compartment.
Explore the source record for details and available documents.
Milk replacers containing all milk protein, 25% of protein from porcine plasma protein, 25% of protein from bovine plasma protein, or all milk protein plus probiotic were compared in a 6-wk experiment using 120 Holstein bull calves approximately 7 d of age. All replacers contained an antibiotic except the one that contained probiotic. Calf starter always was available, and calves were weaned when they consumed 680 g/d of starter. Ten calves were selected randomly from each group for sampling of jugular blood at d 1 and 10 of the experiment. A complete blood count was conducted on the samples, and protein fractionation by electrophoresis was performed on sera harvested from the samples. Mean BW gains started to differ at the end of wk 3, and by the end of wk 6 the difference of 2.6 kg was significantly greater for those calves fed porcine or bovine plasma than for calves fed all milk protein (with or without probiotic). The same response was noted for starter consumption; the difference increased to 4.15 kg by the end of wk 6. Most measurements of blood did not differ by treatment; those that were different did not suggest an apparent difference in performance response. Growth performance of calves fed probiotic was not different from that of calves fed antibiotic when both replacers contained all milk protein. Either porcine or bovine plasma protein was an acceptable source of protein.